The contractor is requested to determine the stability characteristics of crude and partially purified human interferon (to be supplied by the National Institute of Allergy and Infectious Diseases) at -70 degrees C, -20 degreed C, +4 degrees C, room temperature (with and without shaking, only at room temperature), and at +37 degrees C. Accelerated stability tests will be required. The material supplied for evaluation will be identical to that intended for human use, i.e., human proteins, no antibiotics, etc. These studies are to be performed on materials which would be stored in the wet frozen and lyophilized state. Once the areas of instability are defined, methods of stabilizing the interferon by the addition of human albumin or other human proteins (hepatitis free), salts, pH, O2, N2, inert gases, and any other methods suggested by the contractor should be pursued. Only materials suitable for eventual use in humans should be considered.